The present invention relates in general to high pressure expansion mandrels and, more particularly, to a high pressure expansion mandrel for use in the radial expansion of a metal tube for providing a leak-proof joint between a metal tube and a sheet of metal.
In the patent to Kelly, U.S. Pat. No. 4,502,308, issued on Mar. 5, 1985, for Swaging Apparatus Having Elastically Deformable Members With Segmented Supports, there is disclosed a swaging mandrel to be inserted into a tubular structure that is radially expandable. A pair of seals define the axial boundaries of an annular pressure zone between the swaging mandrel and the tubular structure. The seals include an annular support formed by arcuate segments elastically held together. The annular support is formed at one end with a camming surface. At the other end of the annular support is a band which restrains axial movement of the annular support. At the one end of the annular support is a cam which engages the camming surface of the annular support to expand the annular support radially in response to swaging pressure.
The patent to Kelly, U.S. Pat. No. 4,414,739, issued on Nov. 15, 1983, for Apparatus For Hydraulically Forming Joints Between Tubes And Tube Sheets, discloses a mandrel. The mandrel includes an elongated, generally cylindrical body and a head. The mandrel is inserted into a tube that is positioned in the bore of a tube sheet. Pressurized hydraulic fluid is supplied through an axial passageway in the body that is continued by a cross-bore permitting hydraulic fluid to enter an annular volume between the body and the interior wall of the tube. The outer boundaries of the annular volume are between spaced O-rings which encircle the body.